I also saw the first few moves, and concluded it was rather easy for a Friday.

Didn't see that white could cleverly escape the crazy rook by way of the h-file (actually, using his own rook's control of the g-file to limit the black rook's checking options).

So, was this sort of a "spoiler" then? It seems like a rather bad spoiler since black's option are:

1. stupidly try the crazy rook stalemate (which might lose), or

2. brilliantly forsee that it fails, and thus resign (which definitely loses).

Pretty terrible endgame by white, easiest win to me looks like

That's according to Rybka, but is actually one of the worst moves black could make. Black's only hope is a swindle for a draw. This is one key difference between humans and computers. Rybka likely would have lost that game>

I haven't read the complete post so perhaps my question has already been answered... But here goes anyways:

My question concerns a situation like the one in this game, but in the context of a blitz game (or even time pressure)..

If I'm black in this position, and I keep checking the white King (perpetual) but I have LESS time than white. Is it still possible for me to lose on time?

You can lose on time until a player is mate - OR until you can claim a draw, and there is AFAIK only 3 such situations:

1. 3 times repetition - you must claim _before_ you make the move that would be the third time, and before your time runs out.

2. The 50-moves rule, no pawn moved and no captures made for 50 move (and then there are some exceptions with more moves). As above, before you move and before time runs out.

3. It would be technically impossible for your opponent to mate you.

In all other cases, draws must be agreed.

- - -

Don't forget the stalemate. I was brought up being taught the four drawing possibilities:

1 - by agreement
2 - threefold repetition of position
3 - 50 move rule
4 - stalemate

All other draws are really a form of one of these draws.

White threatens an immediate made with Ra8+. But if the two black rooks can be removed from the board, the black king and pawn have no moves, and thus a draw will result.

So....black starts the checks, but must make sure that the white rook on g2 does not have the opportunity to move from the g file (unless the white king gets to f7).

Bearing all this in mind, I think we need to start with 42...Re2+. Now if 43. Kxe2 Re4+ 44. Kf1 Re1+ (not 44....Rf5+ 45. Rf2 and with the white rook having left the g file black can play Kg8). 45. Kf2 Re2+ 46. Kg3 Re3+ Now if 47. Kh2 Rh3+ and black can continue the checks. If 47. Kh4 Rh3+ (not Re4+) 48. Kg5 Rh5+ 49. Kf4 Rf5+ etc. Wherever the white king moves - even in amongst the Q side pawns, black can continue in this fashion (possibly taking some of the pawns in the process. If white captures with the rook on a6, still it will be stalemate.

If white does not play 43. Kxe2, black continues checking as above.

This doesn't seem difficult enough for a Friday puzzle, and I am wondering if I have missed someting.

Very clever idea by <Resignation Trap>.

I asked because I always wondered how perpetuals end. I guess at one point the position must be repeated a third time (but this means you have to KNOW that this is the case... not always easy) or by mutual agreement. I suppose white could always refuse the draw offer, knowing that black is about to lose on time and hoping he won't be able to note the position to gauge the 3-fold repetition (he's in time pressure) ... Hmm ... I would be one frustrated chess player if I were in this situation..

<LucB: one point the position must be repeated a third time (but this means you have to KNOW that this is the case... not always easy)> Most perpetuals are simple, with the opponent having only a few moves, so the "3rd time" is very obvious. Usually, players just agree on a draw, without ever reaching a position a third time. In about 300 tournament games I've had about a dozen perpetuals - all of which were agreed as draws without anybody claiming the 3-times rule.

But as the tournament leader I watched this one, with White to move. It had been an exiting game and there were at least 20 bystanders, with me in front, next to the table:

click for larger view

Black has just played -,Nc4-d2. White to move has less than half a minute left (at that time we played with mechanical clocks, so it was an estimate), Black a couple of minutes.

White has two obvious perpetuals. Simplest is checking on c8 and c7, and claim the draw before checking on c8 the third time. But unfortunately for White he played Qxc6+ and Black answered Kb8, to Which white played Qb6+ and said "Draw!". Black lifted his right hand, and White did the same, expecting a handshake.

Then Black moved his king to c8. White stared in disbelief for 2 seconds, then followed Qc6+,Kd8 Qd6+,Ke8 - all the way to the h-file and back again to the a-file and then again towards the h-file. White shouted "Draw!" a several times, but both players kept moving, without keeping score.

Then White ran out of time. A quick reconstruction of the game (was easy :-) showed that not enough moves had been made to pass the next limit. Bystanders, mostly from Black's club, attacked Black for bad sportmanship, and within less than a minute he said "Sorry, shouldn't have done it. You know, the heat of the moment. Of course I accept a draw".

Then somebody pointed out that White could have claimed the draw, as the position with Qc6/Kc8 clearly had appeared 3 times.

But there was still one bad guy left - me! As I had no other option than to award Black the full point. A painful and unpopular decision.

- - -

Wow, what a story! Thanks again for that info; it was along the lines of the kind of situation I was trying to get at... of course they won't write down their moves.. They're kind of in blitz mode (at least the one running out of time).

Rybka 3 1-cpu: 3071mb hash: depth 20:

Black made many less than optimum moves including:-

+2.02 26...f3 better was c3 +1.24

+4.11 36...Rh4 " " Re1 +3.61

+5.09 39...Rd5 " " Red8 +4.34

After 42. ... Rf5+; 43. Kxe1, Rf1+ if White captures the Rook Black is stalemated. If 44. Ke2, Re1+ and Black keeps up the pursuit. Sooner or later White will have to take, stalemating Black, or the position be repeated 3 times, again a draw.